Puffed food starch product and method for making the same

ABSTRACT

The present invention includes a method of making a puffed-food starch material snack, in particular starch material from grains, having an improved crispy texture and a more aesthetic appearance. The products may be snack chips, cakes, crackers or the like, made from food starch material. Preferably, the starch material is provided primarily in the form of individual kernels or pellets of a cereal grain, such as rice, corn, wheat, rye, oats, millet, sorghum, barley, buckwheat, or mixtures thereof. According to one method, a puffing chamber is provided having inner surfaces and a chamber volume. A bulk amount of the food starch material is placed into the puffing chamber. The bulk amount of food starch material is caused to volumetrically expand. The expanding food starch material is constrained in its expansion in at least a first dimension, while permitting unconstrained expansion of the bulk amount in at least a second dimension.

This is a continuation of U.S. application Ser. No. 09/281,991 filed onMar. 29, 1999, now U.S. Pat. No. 6,569,481, issued May 27, 2003.

TECHNICAL FIELD

This invention relates generally to improved puffed food starch productsmade from cereal grains or other food starches, forming such productsinto various shapes, and the methods for their manufacture. Moreparticularly, the present invention relates to puffed-rice snacks withimproved crispiness, and appealing visual and physical texture, andprocesses of preparing such snacks.

BACKGROUND OF THE INVENTION

Snacks have long been a household staple around the world and range fromtreats to dietary supplements. However, not too long ago a nutritiontrend found chocolates, candies, ice cream, and other naturally andartificially sweetened confections, as well as potato chips, pretzels,corn chips, and the like, being replaced by more healthy products. Theterms “low fat,” “no-fat,” and “light” have become the watch words ofthe health conscious in the '90s. The trend has seen the popularity ofpuffed snacks, sometimes referred to as popped grain snacks andespecially those made of corn and rice, steadily climb.

Very successful products have been made in the form of cakes generallymade of puffed corn or rice. While these products had a heretoforeacceptable amount of crispiness, they suffered from an unpleasanttexture, usually nearest the core of the cake, resulting in the productsticking in teeth. The products are hockey puck-shaped (uniform in allthree dimensions) and lack the appealing visual texture of conventionalsnack foods. These snack cakes are also relatively large (approximatelya three to four-inch disk-shaped cake). This size, as a single portion,can lead to a substantial amount of waste for some consumers, especiallychildren. To address the problem of waste, a “mini-cake,” or smallerversion of the original cake (about a one to two-inch disk-shaped cakeor cracker) was introduced. The problems of texture and appearance,however, remained.

Examples of methods for making conventional grain cake products aredisclosed in the described methods of U.S. Pat. No. 4,888,180 to Wu.These cake-forming devices are most frequently used with rice as thecereal grain since rice is capable of relatively easy expansion into aself-supporting cake. Statistics show that the availability andversatility of rice have not only made it an industry favorite, but aconsumer favorite as well. The annual world rice harvest in the early1990s exceeded 510 million metric tons, an increase of about 30 percentover the average during the period from 1979 to 1981. Rice grains areextensively used as human food, constituting the principal food ofalmost one-half the human race. The leading rice producers are China,with 36 percent of world output in the early 1990s, and India, with 22percent. In the United States, production averaged close to 7 millionmetric tons, with Arkansas, California, Louisiana, and Texas being theleading rice-producing states.

Rice puffing and, in general, cereal puffing (or cereal popping) methodsare well established in the prior art. Generally, methods known in theart rely primarily on a moisture content in the grains for puffing. Themoisture content can be varied by many processes, such as, drying,cooking, parboiling, and tempering. Examples of attempted improvementsin processing methods are described in U.S. Pat. No. 4,281,593 toGevaert, U.S. Pat. No. 4,328,741 to Yoshikazu, and U.S. Pat. No.4,667,588 to Hayashi.

There are two generally practiced methods for expanding or puffinggrains: (1) heating the kernels of grain until they become extensible(i.e. until the starch becomes amorphous or flowable) at which pointfurther heating permits evaporation of moisture (and out-gassing of someminor amounts of other gases entrained in the grain) which causesexpansion (bubble formation) in the amorphous starch; (2) heating thegrain kernels to a flowable state at atmospheric pressure, then suddenlyreducing the pressure (partial vacuum) again permitting enhancedvaporization and out-gassing, and again causing expansion (bubbleformation) in the amorphous starch; and (3) heating the grain kernels toa flowable state in a chamber where pressure is permitted (or caused) tobuild, then suddenly reducing the pressure to atmospheric, permittingenhanced vaporization and out-gassing and again causing expansion(bubble formation) in the amorphous starch.

This latter method is most conventionally used to make rice cakes ofboth the larger and “mini” sizes. This latter method is carried out inwhat is commonly referred to as rice popping machines. These machinesprovide a chamber defined by heated chamber walls. Once the pre-puffedgrain is placed in the chamber, it is closed to a pressure seal. Thefood starch is heated by contact with the chamber walls. The amount offood starch, i.e. the amount of grain kernels loaded into the chamber,relative to the volume of the chamber, and amount of expansion, causethe puffed product to generally conform in all three dimensions to theshape of the chamber.

One problem with conventional rice popping processes is that the fillingof the entire volume of the popping chamber upon expansion may limit thebubble size formed, or full expansion of the bulk amount of the foodstarch, or both. This may account for a less than fully crisped productand a teeth-sticking texture of the resulting rice cake. It is certainlyresponsible for the hockey puck-shape of the product, which heretoforewas thought to be desirable.

Another problem which exists in use of rice popping equipment is tryingto balance providing sufficient time to present good conditions for fullexpansion of the food starch, while at the same time trying to minimizechamber residence time to achieve high production rates. To date, thisbalance has produced the conventional rice cakes discussed above.

It is well known that the degree and ease of puffing is affected by manyfactors such as: the type of grain, the type of preprocessing (e.g.milling), the condition of the grain (e.g. moisture content), and thetype of starch contained in the grain. Another advancement in puffingfood starch is to puff food starch which has been floured, and toextrude it into a discrete size and shape. Such extruded pieces arecooled and dried to a state of desired moisture content and hardness foracceptable handling and storage. To date, such puffing has been limitedto oven puffing or deep frying. The resulting products, however, arerelatively uniform throughout the snack piece, and provide a monolithictexture to the mouth when eating them. The same can be said for theproducts made from the more conventional process of extrusion puffing.

The inventor is unaware of a cake-type product ever being attemptedusing such pelletized stock. Further, it appears that prior to thepresent invention, it has never been contemplated to employ such apelletized pre-product in a rice popping machine or related process.

In sum, despite the improvements being made in the field of makingpuffed snack cakes from food starches, in particular rice grain,insufficient attention has been given to improving the overall visualand physical texture (e.g. crispiness) and appearance of the product.The present invention addresses these issues as well as solving theproblems discussed above and providing other advantages which willbecome apparent to those skilled in the art upon reading theaccompanying specification and claims.

SUMMARY OF THE INVENTION

The present invention provides puffed food starch snacks having animproved crispy texture and a more aesthetic appearance and methods forpreparing them.

In general terms, the products are snack chips, cakes, crackers or thelike, made from food starch. Preferably, the starch material is providedprimarily in the form of individual kernels or pellets of a cerealgrain, such as rice, corn, wheat, rye, oats, millet, sorghum, barley,buckwheat, or mixtures thereof. Quantities of other food starches mayalso be employed as a co-mixed constituent, or as the primary source ofbulk starch material, for example, potato starch. A quantity of the foodstarch is puffed (expanded) in a manner which forms a snack product ofconsiderable crispiness, lightness, and unique texture to both the mouthand eye.

According to one aspect of the invention, a puffed snack productcomprises a puffed starch body having a generally regular perimetricalshape, and opposed upper and lower surfaces. At least one of the upperand lower surfaces has a substantially wavy contour such that it appearsas though individual kernels of grain are joined to one another. It ispreferred that the substantially wavy surface of the starch bodycomprises hills and valleys, noted by the rise and fall of the surfacealong a parallel plane.

In a preferred embodiment, the puffed snack product is comprisedprimarily of rice starch, but may further include puffed corn starch,puffed wheat starch, puffed potato starch, or the like.

In other presently preferred embodiments, the puffed snack product maybe comprised primarily or predominantly of puffed corn starch, puffedwheat starch, or puffed potato starch, with combinations of other suchgrains possible. Presently, a preferred perimetrical shape of the foodproduct is generally circular, hence a rounded cake in two dimensions.Alternatively, other embodiments may include a perimetrical shape whichis generally triangular, square, rectangular, or any other suchgeometric or fanciful shape as may be thought at the time to haveconsumer appeal or processing, handling, or packaging advantages.

According to another aspect of the invention, the bulk cake product iscomprised of an amount of food starch in the form of a plurality ofindividual whole kernels of grain, puffed together. At least a portionof these whole kernels may be rice kernels, wheat kernels, or both, andmay additionally include corn grits.

According to another aspect of the invention, the cake or snack body isformed from a bulk amount of food starch comprised of a plurality ofindividual pellets (formed from starchy flour) all puffed together. Suchpellets are preferably made from rice flour, wheat flour, corn flour,potato flour or the like, and may additionally include corn grits. Asufficient amount of pellets (and corn grits, if desired) capable ofbecoming amorphous in the puffing chamber should be provided, such thatall of the pellets and grits touch at least one other pellet or gritafter becoming amorphous.

According to another aspect of the invention, a puffing chamber isprovided having inner surfaces and a chamber volume. A bulk amount ofthe food starch is placed into the puffing chamber. The bulk amount offood starch material is caused to volumetrically expand. The expandingfood starch is constrained in its expansion in at least a firstdimension, while permitting expansion of the bulk amount in at least asecond dimension.

The step of constraining expansion may additionally include constrainingexpansion of the bulk amount in a third dimension. The constraining mayachieve a defining of the general shape of the final product in thefirst dimension, or in both the first and third dimensions. The definedshape may be provided by, in one particular embodiment, constrainingexpansion with certain of the inner surfaces of the puffing chamber.Preferably, for the snack cake disclosed in the example below, theunconstrained second dimension is height.

Another method of the present invention includes predetermining the bulkamount of food starch material to be placed into the chamber. Thepredetermining should provide a sufficient amount of whole kernels (orcorn grits, if desired) capable of becoming amorphous, such that all ofthe kernels or grits touch at least one other kernel or grit afterbecoming amorphous.

Where pellets are used, the method may further include forming thepellets generally to the size of a whole kernel of grain selected fromthe group of grains including rice, wheat, barley, oats, rye, and corn.

Another aspect of the invention provides for puffing a food starchcapable of becoming amorphous into a food starch product, wherein thefood starch is first floured then pre-gelatinized in an extruder under apressure and temperature. The food starch is then extruded and cut intopellets. The pelletized food starch is placed into a puffing chamberwhere increasing the pressure and the temperature in the chamber causesthe pelletized food starch to become amorphous. By quickly reducing thepressure in the chamber, the amorphous starch pellets expand.

The pellets are believed to provide superior puffing (at least relativeto a given time and temperature cycle in mass production) to wholekernels. While presently unproven, the advantages are believed to bethat: (1) the pellets are pre-gelatinized and may allow more of the heatenergy (in the given cycle time or amount of thermal energy) tocontribute to water vaporization and bubble formation (as opposed toproviding energy to accomplish a greater crystalline phase change) thanin a grain kernel; (2) the pelletized rice has been pre-floured, hencethe mechanical and physical boundaries of the cellular structure havealready been broken down leading to a more uniform expansion with less(heat) energy required to break down the cellular structure; and (3) theuniform pellet structure has a more uniform distribution of both starchand moisture for improved crisp puffing.

According to another aspect of the invention, the extruded food starchpellets may be cooled under sufficiently controlled (slowly) parametersto reduce stress in the pellet (i.e. an annealing of the pellets). Thisshould reduce the energy required for possible annealing in the poppingchamber. Also, the slow drying should enhance endurance of furtherhandling without fracturing. The extruded pellets should be providedwith sufficient drying to enhance shelf life and to prevent pellets fromsticking together in storage.

It is also possible that, once gelatinized, the pellets are cooled insuch a way as to reduce recrystallization of the starch. This may alsoassist in puffing in that for a fixed amount of energy input, energy isnot wasted unduly on annealing in the puffing chamber. However, such acooling may be at odds with the slow cooling for stress reduction. Whileone type of cooling may be used as a trade off for the other, stressreduction presently looks to be the preferred goal.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings,

FIG. 1 is a cut-away side view depicting a puffing machine used in thepresent invention in a completely open position;

FIG. 2 is a similar view of the puffing machine of FIG. 1 showing theplacement of food starch within a couple of chambers;

FIG. 3 is a similar view of the puffing machine of FIG. 1 showing thesealed chambers;

FIG. 4 is a similar view of the puffing machine of FIG. 1 justsubsequent to breaking the seal on the chambers;

FIG. 5 is a similar view of the puffing machine of FIG. 1 showing theupper mold fully retracted;

FIG. 6 is a similar view of the puffing machine of FIG. 1 showing thefinal product being ejected from the mold;

FIG. 7 is a top view of a supply plate for the present invention;

FIG. 8 is a perspective view of a puffed food starch product made inaccordance with one embodiment of the present invention;

FIG. 9 is a top view of a puffed food starch product as shown in FIG. 8;

FIG. 10 is a bottom view of a puffed food starch product as shown inFIG. 8;

FIG. 11 is a first side view of a puffed food starch product as shown inFIG. 8;

FIG. 12 is a second side view of a puffed food starch product as shownin FIG. 8;

FIG. 13 is a third side view of a puffed food starch product as shown inFIG. 8;

FIG. 14 is a fourth side view of a puffed food starch product as shownin FIG. 8;

FIG. 15 is a perspective view of another puffed food starch product madein accordance with one embodiment of the present invention;

FIG. 16 is a perspective view of another puffed food starch product madein accordance with one embodiment of the present invention;

FIG. 17 is a perspective view of another puffed food starch product madein accordance with one embodiment of the present invention;

FIG. 18 is a flow chart illustrating an embodiment of the present methodfor producing a puffed food starch product;

FIG. 19 is a flow chart illustrating another embodiment of the presentmethod for producing a puffed food starch product using pelletized foodstarch; and

FIG. 20 is a flow chart generally illustrating the operation of thepuffing machine.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

While the invention is susceptible of embodiment in many differentforms, this disclosure will describe in detail preferred embodiments ofthe invention with the understanding that the present disclosure is tobe considered as an exemplification of the principles of the inventionand is not intended to limit the broad aspect of the invention to theembodiments illustrated.

Product

The puffed or popped food starch products of the present inventionprovide a number of advantages over prior puffed food starch cake orcracker products. It is believed that the products are lighter,crispier, and have a more appealing visual texture as well as texture tothe mouth when consumed. In some cases products made in accordance withthe invention are believed to have a more natural, unprocessedappearance, as illustrated in FIGS. 8–17.

However, the wavy, natural appearance provides functional advantagesover the prior art as well. The undulating surface allows snack dips tobe more easily scooped, much like a potato chip or corn chip, than thehockey puck-shaped cakes. Additionally, the present product may besprinkled with flavoring during manufacturing, including such savoryflavors as barbeque, sour cream, cheese, garlic and onion, and most anyother popular snack flavor. The highly textured surface provides longerretention of granular or crystalline flavor coatings. Additionally,because the top and bottom surface areas of each chip are larger than astandard flat surface of prior art cakes, a greater amount of flavoringmay be applied. More flavoring may improve the overall flavor of aproduct that has enjoyed past commercial success.

Products according to the invention may be in the form of a snack chip,cake, or cracker. They can be made from individual kernels according tocertain aspects of the invention and from individual pellets of extrudedfood starch material according to other aspects of the invention.Disclosed herein are cakes made from a cereal grain, such as rice, corn,wheat, rye, oats, millet, sorghum, barley, buckwheat, or mixturesthereof. A quantity of the grain is puffed (expanded) in a manner whichforms a snack product of considerable lightness and crispiness overprevious puffed-grain snacks.

The puffing phenomenon results from the sudden expansion of water vapor(steam) from moisture held within the starch material of the granule(and some out-gassing). The particle is fixed in its expanded state bythe dehydration resulting from the rapid diffusion of water vapor out ofit. The moisture level is considered an important factor in puffinggrain. Before puffing, the grain or pellet preferably should bemaintained at no less than 3% moisture in order to achieve the desiredextent of puffing and crispness of the final product. The preferredembodiment has a moisture content which falls within the range of fromabout 8% to about 18% (by weight) moisture, with about 8% to about 13%(by weight) being more preferred, and about 10% to about 12% being themost preferred moisture content. Moisture contents outside of the 8–18%range may cause a decreased puffing on the one hand, and collapse of analready puffed product on the other hand.

Rice grain is preferred for many reasons, including its capability toexpand with relative ease into a self-supporting cake product. FIGS.8–14 show various views of one embodiment of a snack cake according tothe present invention. The puffed snack product of the present inventioncomprises a puffed starch body 10 having a generally regularperimetrical shape, and opposed upper and lower surfaces 12, 14. Theperimetrical shape of body 10 is circular. Other shapes arecontemplated, for example, other geometric shapes: triangular, square,rectangular, etc., and fanciful shapes may provide particular advantagesin some instances. FIGS. 15–17 show food starch products with surfacevariations.

Referring to FIGS. 8–14, the upper surface 12 and the lower surface 14have a substantially wavy contour, and each surface 12, 14 has a generalappearance which permits visual discrimination between individualkernels of grain 16 as they are joined to one another. It is preferredthat the substantially wavy surface of the starch body 10 compriseshills 17 and valleys 18, noted by the non-uniform rise and fall of thesurfaces 12, 14.

While the preferred starch body 10 is comprised primarily of rice, itmay further include corn, wheat, potato, oats, rye, barley, buckwheat,or any combination of these or other suitable sources of puffable foodstarch. Hereafter, the terms “good” or “goods” are intended to describestarch-bearing materials, including cereal grains, seeds, tubers, andthe like, which are used in the present process to make up the foodstarch of the starch bodies such as body 10 or in making up the bulkamount of food starch placed in the puffing chamber. Where applicable,these goods may be supplied in the form of ground flour, whole kernels,or in a pelletized form. Mixtures of goods in the form of flour, ormixed whole kernels or mixed pellets may also be used in accordance withthe present invention, with varying results. Mixtures of goods in theform of flour, or mixed whole kernels or mixed pellets may also be usedin accordance with the present invention, with varying results.

With respect to flour and whole kernels, single goods or mixtures ofgoods may be used to create a suitable puffable food starch composition.As rice is the preferred food starch in the disclosed embodiment of body10, it should be understood it will be the preferred predominant goodused in mixtures for many of the disclosed methods. A predominantly riceflour mixture may contain rice flour within the range of about 51% to100% by weight. Similarly, a predominantly corn flour mixture would bepredominantly corn flour (i.e., at least 51% by weight). The remainingpercentage, up to 49% by weight, may be made up of any one or more ofother floured goods. This is equally true for a mixture of predominantlyrice grain, or predominantly corn grit (i.e., cracked corn). It shouldbe noted that moisture content of the respective starch constituents iscounted in its weight percentage.

Pellets are more variable than either flour or whole kernels. Thepellets themselves may be made from a mixture of goods from a flourform, and the entire composition may be comprised of several differentkinds of pellets. For instance, “A” pellets may be formed from a mixtureof 75% by weight rice flour and 25% by weight corn flour, while “B”pellets may be formed from 60% by weight rice flour and 40% by weightpotato flour. A first recipe may call for 50% by weight of “A” pelletsand 50% by weight of “B” pellets, while a second recipe may require 90%by weight “A” pellets and only 10% by weight of “B” pellets. The variouscombinations are nearly infinite.

Of the three forms of goods disclosed, pellets are a preferred form,according to a separate aspect of the invention. Pellets provideexcellent textural features (e.g., crispiness, contour, etc.), produce ahigh-quality puffed product, and allow more precise control of moisturecontent. While rice is the preferred good for the pelletized form in thepresent invention, other embodiments of the puffed snack product may becomprised primarily of corn, wheat, or a puffed potato starch, withcombinations and other such grains (or starches from sources other thangrains) also possible.

Part of what gives the present invention its unique surface contour isthe composition of the bulk food starch. The various goods will all havedifferent expandability, partly dependent upon moisture content andpartially due to the differing starch characteristics, compositions, orpre-processing (such as pre-gelatinization). By assembling a bulk foodstarch of predominantly rice (either flour, whole kernels, or pellets)interspersed with, for instance, the preferred corn grits, the puffedproduct will have natural surface and texture variations due to variedexpansion. Therefore, to facilitate this effect in the presentinvention, at least a portion of the bulk food starch in certainembodiments will be enhanced by the inclusion of corn grits which do notexpand as much as rice pellets or kernels.

Referring again to FIGS. 8–14, regardless of the good(s) or form used,according to one aspect of the invention, the product has a generallypredefined perimetrical shape. Preferably, the perimetrical shape of thefood product is one that is appealing to consumers and is suitable foruse in a chamber-type popping machine. Applicant has found a circularshape to meet both of these requirements. It is also believed that theremay be textural advantages of the circular shape.

In order to form the preferred product, which is more easily understoodwith reference to the described methods, a sufficient amount of wholekernels or pellets (and corn grits) capable of becoming amorphous,should be provided such that all of the whole kernels or pellets (andgrits) touch or contact at least one other whole kernel or pellet (orgrit) after becoming amorphous. In other words, the bulk food starch iscapable of melting into a single flowable mass. This means that theamount of bulk food starch used for making the present inventive productis an important feature, as discussed below.

The area of contact between two or more of the kernels or pellets form aconnective boundary after they become flowable. This boundary definesthe area of connection between kernels or pellets. The preferred puffedproduct is most readily broken apart at these boundaries, as opposed tobreaking within the body of the puffed kernel or pellet. This adds tothe aesthetic appearance of the product according to the presentinvention. Prior art grain cakes are typically comprised of indistinctor less distinguishable boundaries between puffed kernels, breakingalong less visually determinable lines.

Another textural distinguishing aspect of the present invention over theprior art relates to the product thickness. The preferred product istypically a single layer, approximately one grain thick. This helpsinsure contact between individual kernels, pellets, and grits occurs onno more than two dimensions (i.e., primarily side-to-side connection).This, in turn, insures the added eating textural appeal of individualkernels or pellets in each puffed product. Conversely, the prior artcakes are several grains thick, causing three dimensional contact (i.e.,side-to-side and top-to-bottom connections). Such, three-dimensionalcontact removes the added aesthetic and textural crispiness and appealof the individual kernels or pellets within the cake. This again relatesto the amount of bulk food starch relative to the puffing chamber volumeand resting area.

Processes

In many prior art processes, an amount of food starch (in whole kernelform only) is added to a puffing chamber so that upon expansion the foodstarch fills the entire chamber. The result is a puffed productconformed exactly to the size and shape of the chamber, in substantiallythe form of a disk. This is very different than the present invention.

A preferred method of making the puffed food starch product of thepresent invention, illustrated in FIG. 18, utilizes a bulk amount of apreviously described food starch. The disclosed method begins byproviding a puffing chamber having inner surfaces and a chamber volume,and then placing a bulk amount of the food starch material into thepuffing chamber. Generally speaking, the bulk amount of food starch iscaused to volumetrically expand. In other words, the bulk food starch ispuffed to several times its original size.

Puffing machines (usually having a plurality of chambers each) arewidely known and understood by those skilled in the art. A suitablepuffing machine is manufactured by REAL FOODS PTY, LTD. of St. PetersNSW, Australia. Referring to FIGS. 1–6, puffing chamber 20 is shown,generally, having an opening 21 on ring mold 22, upper mold insert 24(attached to an upper base 25), and lower mold insert 26 (attached to alower base 27). Each of these components may be slidably movable onguide pins 28, though ring mold 22 is typically fixed. The mold inserts24, 26 (via bases 25, 27) may be actuated hydraulically, pneumatically,or in any other suitable manner. As shown in FIGS. 2 and 3, mold inserts24, 26 enter opening 21 to form the inner surfaces of the puffingchamber.

The present preferred method requires constraining the expansion of thebulk amount of food starch in at least a first dimension, whilepermitting expansion of the bulk amount in at least a second dimension.In other words, the food starch is capable of expanding to its fullvolumetric potential (taking into account moisture content of the foodstarch, temperature of the chamber, and the forces of gravity), whilebeing prevented from expanding in one of either height, width, or depth.For example, if the height of the puffed product is constrained, thenthe width and depth of the puffed product proportionately increase.Where two dimensions are constrained, the third will compensate toachieve total volume expansion. At no time is the total volumetricexpansion of the puffed product constrained by the inner surfaces of thepuffing chamber, while dimensional expansion is constrained. Preferably,this may be achieved by predetermining the proper amount of the bulkamount of food starch placed into the puffing chamber relative to thetotal volume of the chamber in an unsealed (puffing) condition. Priorart processes attempt to completely fill the chamber (at least uponpuffing).

Using the puffing chamber for dimensional constraining may be achievedby defining a general shape of the product (as discussed previously) inthe first dimension, or in both the first and third dimensions. Theconstrained shape may be provided by, in one particular embodiment,constraining expansion with the inner surfaces of the puffing chamber.

Balanced against the unconstrained volumetric expansion aspects of thepresent invention (i.e., properly sizing the bulk amount of food starchplaced into the puffing chamber) is the necessity to produce a single,unitary product from the puffing chamber. With these competing interestsin mind, the present method may further include predetermining the bulkamount of food starch to be placed into the chamber, such that there isa sufficient amount of whole kernels or pellets (or corn grits) that allof the kernels or pellets (and grits) touch at least one other kernel orpellet (or grit) after becoming amorphous.

While the exact mechanism of how the food starch bonds together in thepuffing chamber is not fully understood, referring to FIG. 20, it isbelieved that a melt occurs, or at least a softening or gelatinizationof the food starch. In a preferred embodiment of the invention, thepuffing chamber 20 is heated to a temperature of about 475° F. (about246° C.). Puffing machines, as well as individual puffing chambers,however, can vary greatly from one to another. Due to such differences,and any other prevailing conditions which may exist (e.g., the amountand type of food starch and its preprocessing history), the chambertemperature may range from about 350° F. (about 177° C.) to about 550°F. (about 288° C.), including any combination or sub-combination ofranges within this range. As the chamber is sealed and the food starchis heated, the internal pressure of the chamber increases, though afinal pressure has not been measured. No additional pressure is added tothe chamber in the preferred embodiment, but may be implemented foralternative embodiments.

Referring to FIG. 7, a supply plate 30 is shown. Supply plate 30 isshown having seven (7) openings 32, but may contain more or less to suitparticular manufacturing needs. Openings are preferably about 0.563inches diameter by about 0.591 inches deep (about 0.147 cubic inches) toallow a sufficient amount of bulk food starch to pass through forpuffing an approximately two inch (2″) product, but these dimensions mayvary for larger or smaller products. The volume of opening 32 determinesthe amount of food starch to be added to each chamber. Each opening 32corresponds to a chamber 20 of the puffing machine. As supply plate 30moves across the open ring mold 22, it deposits the predetermined amountof bulk material filling each opening volume into the chamber 20, torest on lower mold insert 26. Supply plate 30 is then retracted.

The chamber is closed as shown in the sequence of FIGS. 2–5, and thebulk food starch is heated to an amorphous or extensible state. After anapproximate 5.25 to 6.75 second heating cycle time, upper mold insert 24raises to release pressure in chamber 20, as shown in FIG. 4. Then uppermold insert 24 completely raises and lower mold insert 26 raises tobecome flush with the upper surface of ring mold 22, as shown in FIG. 6.Finally, supply plate 30 returns to make a subsequent deposit, pushingthe puffed food starch products to a discharge chute (not shown) in theprocess.

The amount of food starch used in the present invention is less thanthat used in prior art processes. A relationship exists between the massof food starch used and the expansion of the final product, also takinginto consideration the chamber volume (about 0.79 cubic inches in thepresent invention), cycle time, and chamber temperature. Basically, theexpanded food starch should not be constrained by the chamber volume, asdiscussed above. Another consideration, however, is the placement of thefood starch within the chamber. If the food starch is thick or moundedon top of itself, then expansion of the food starch as a whole will bediminished. Thinly spread food starch will tend to puff more completely.

Where pellets are used in the present invention, it is considered to bewithin the knowledge of those skilled in the art to prepare suitablepellets. The J. R. SHORT COMPANY, Chicago, Ill., manufactures such arice pellet. Basically, referring to FIG. 19, beginning with a flouredfood starch, the starch is gelatinized in an extruder under a pressureand temperature. The food starch is then extruded and cut, formingindividual pellets. The pellets, in the preferred embodiment, are formedgenerally to the size of a whole kernel of grain. The grain size can beselected from the group of grains including rice, wheat, barley, oats,rye, corn, etc. The extruded food starch pellets may be cooledsufficiently (i.e., slowly) to substantially reduce any stress in thepellet, and to provide sufficient drying to provide good shelf life andprevent extruded food starch pellets from sticking together in storage.

In another preferred embodiment of the present method, Applicant foundadvantages in pelletizing the food starch material, and then placing anamount of the pelletized food starch into the puffing chamber. Theamount may be as little as a single pellet, or as many as suitable forthe chamber size. The pellets within the chamber are then caused tovolumetrically expand and form a suitable cake or chip.

Another major advantage of the use of pellets over whole kernels is thatthe pellets need not be tempered prior to puffing. Tempering is aprocess whereby the whole kernels are tumbled in a high moistureatmosphere (frequently steam is used). This is not necessary forpellets. The moisture content of the pellets is controlled atmanufacture, most preferably within the range of about 10% to about 12%(by weight). Additionally, the tempering process is used to increase thepuffability of the kernels, as described above. Pelletization appears toprovide sufficient enhancements to puffability to negate the need fortempering.

While specific embodiments have been illustrated and described, numerousmodifications are possible without departing from the spirit of theinvention, and the scope of protection is only limited by the scope ofthe accompanying claims.

1. A method of making a puffed food starch material product, which foodstarch material is capable of volumetric expansion in three dimensions,namely width, depth and height, during puffing thereof, the methodcomprising: providing a puffing chamber having inner surfaces and achamber volume; placing a food starch material pellet into the puffingchamber to form a single, unitary puffed food starch material productupon puffing in the chamber; causing a volumetric expansion of the foodstarch material pellet placed in the chamber to form a single, unitarypuffed food starch material product by constraining expansion of thefood starch material pellet in the chamber in at least a firstdimension, while permitting unconstrained expansion of the food starchmaterial pellet in at least a second dimension.
 2. The method of claim 1wherein the food starch material pellet is a man-made pellet formed bygelatinizing starchy flour and forming the gelatinized starchy flourinto a pellet.
 3. The method of claim 2 wherein said food starchmaterial pellet is a single pellet.
 4. The method of claim 3 furthercomprising heating the pellet to an amorphous state and volumetricallyexpanding the amorphous starch material to form a puffed unitaryproduct.
 5. The method of claim 3 further comprising placing a pluralityof corn grits into the chamber and volumetrically expanding the corngrits and pellet into a puffed unitary product.
 6. The method of claim 3wherein the pellet is composed of flour selected from the groupconsisting of rice flour, corn flour, wheat flour, potato flour, oatflour, rye flour, barley flour, buckwheat and combinations thereof. 7.The method of claim 6 wherein the pellet comprises at least 50% riceflour.
 8. The method of claim 6 wherein the pellet comprises at least50% corn flour.
 9. The method of claim 6 wherein the pellet comprisesabout 75% by weight rice flour and about 25% by weight corn flour. 10.The method of claim 6 wherein the pellet comprises about 60% by weightrice flour and about 40% by weight potato flour.
 11. The method of claim1 further comprising constraining expansion in a third dimension. 12.The method of claim 1 wherein said puffed unitary product has agenerally perimetrical shape.
 13. The method of claim 1 wherein thepuffed unitary product has top and bottom sides and comprises a wavycontour on at least one of the top and bottom sides.
 14. The method ofclaim 1 wherein said puffed unitary product does not fill the entirepuffing chamber.
 15. A puffed snack product made by the method of claim1, wherein said product has a generally regular perimetrical shape andopposing sides, and wherein at least one side has a wavy contour andappears as though individual kernels of grain are randomly joined to oneanother.